The disclosure concerns a tandem printing system and a method to control such a printing system, as well as a computer system and a computer program product.
Tandem printing systems comprise at least two printing apparatuses that are connected with one another (in terms of control systems) in a detachable manner. The disclosure concerns a tandem printing system that in particular has two digital high-capacity printing apparatuses and that is optionally operable in a simplex operating mode and a duplex operating mode. In particular, in a simplex operating mode each of the two printing apparatuses can process print jobs independent of a respective other printing apparatus, without the printing apparatuses being connected with one another in terms of their control, and in a duplex operating mode print jobs can respectively be processed jointly by both printing apparatuses, wherein they are connected with one another in terms of their control.
For example, such digital high-capacity printing systems are used in print production centers in which print goods are generated with high speed. Print jobs in such print centers are in particular individualized per page, and typically are comprised of a few hundred to hundreds of thousands of pages. The processing of the pages therefore requires both a high data processing speed in the processing of print jobs and a high print speed in the printing device. Typical print speeds of a few hundred to multiple thousands of A4 pages per minute are thereby typically achieved. For example, the print technology can be based on electrographic or magnetographic methods, or on the principle of inkjet printing; however, it is not limited to these technologies and can also comprise a combination of multiple technologies, for example of printing system parts that print by means of offset methods and printing system parts that print by means of the inkjet technique.
From U.S. Pat. No. 4,774,524 A a digital tandem printing system is known in which the two printing apparatuses are connected on a first control layer (data control layer) to a common external data source, namely to a host computer that supplies print data to the printing apparatuses. The printing apparatuses are additionally connected with one another directly in terms of their control on a second control layer (device control layer), via which they are synchronized such that the page association between the images printed by both apparatuses is correct. This is important in particular given a double-sided printing (duplex printing) in which the front side of documents to be printed is respectively printed by the first printing apparatus and the back side is respectively printed by the second printing apparatus.
In the publication “Digital Printing, M. Hoffman-Falk (publisher), Océ Printing Systems GmbH, 9th edition (2005), ISBN 3-00-00108-5, a computer system for a raster image controller with the brand name Océ SRA Controller is described on Pages 250 through 258. A computer system with a print server for high-capacity printing systems with the brand name Océ PRISMAproduction Server, with which print jobs are administered and output to print apparatuses, is described on Pages 347 through 361.
Computer modules with which computers can be modularly combined like plug-in cards into a computer system are offered and distributed by the Hewlett-Packard Development Company, L.P. (hp) under the name HP Blade System c3000. They are described in the brief description “QuickSpecs”, hp Publication Number DA-12790 Worldwide, Version 31 (15 Nov. 2010), which is available as a PDF document on the Internet. What is known as the enclosure thereby corresponds to a frame on which infrastructure components (such as power supply, fan or even network interfaces) are already located beforehand, which components are respectively used jointly by the respective inserted plug-in cards. Moreover, the plug-in cards (blades) for their part are respective powerful computers with typical structural elements such as microprocessors (CPUs), memories etc.
If printing apparatuses of a tandem printing system are operated individually, independently of one another, typical individual different apparatus adjustments are then made in the respective apparatuses, for example with regard to the supported page description languages (PDLs) of the print job data, for example Page Definition Format (PDF), PostScript (PS) or Intelligent Printer Data Stream (IPDS). Parameters such as width, length or type of the recording material, print speed, print image resolution and type and number of the printing substances or printing inks can also be set differently. However, certain settings must be the same in both apparatuses for the duplex mode, for example the supported page description language. However, the reconfiguration of such settings can mean a significant cost because it demands a plurality of new data to be loaded and activated, and even requires a complete restart of the respective apparatus with the new settings under the circumstances.
This can be time- and work-intensive and reduce the productivity of the apparatus, in particular if an operator must simultaneously monitor (and possibly adjust) multiple printing apparatuses in a print center.
A method to configure the apparatus settings of a printing apparatus in the course of the activation process is known in U.S. Pat. No. 7,199,886 B2, wherein the support for page description languages can be configured (among other things).
In the US patent application (submitted simultaneously with this Application) with the applicant's Ser. No. 13/357,125 and the title “PRINTING SYSTEM WITH MULTIPLE DATA BUS SEGMENTS”, a tandem printing system is described in which internal apparatus controllers of the two printing apparatuses (printing units) can be connected with one another via a control line (in particular via a CAN bus) so as to be detachable, wherein the connection is detached in simplex mode and the connection is established in duplex mode. Each printing unit has multiple sub-modules (apparatuses) with a respective microprocessor controller, wherein the microprocessor controllers of a printing unit are connected with one another with a respective data bus segment. Each data bus segment has multiple data lines. The at least two data bus segments of the two printing units are connected with one another with a bus switch. For each data line the bus switch has a respective data switch to connect a respective data line of the one data bus segment with the corresponding data line of the other data bus segment, and a respective terminating resistor for each data bus segment, wherein the terminating resistors are connected in series with a respective terminating switch, and the terminating switches are coupled with the data switches such that either all terminating switches are opened and all data switches are closed, or all terminating switches are closed and all data switches are opened.
The aforementioned publications or, respectively, the contents of the patent applications are herewith incorporated by reference into the present Specification.